Production of artificial filaments, threads and the like



March 1957 E. E. TALLIS ETAL 2,784,107

PRODUCTION OF ARTIFICIAL FILAMENTS, THREADS AND THE LIKE Filed Nov. 12.1952 'lm/ rs Ernest Ed r Tall/'5 John Harold Edwards By their afiorneysPRODUCTION OF ARTEFICIAL FILAMENTS, THREADS AND THE LIKE Ernest EdwardTailis and John Harold Edwards, Coven= try, England, assignors toCourtaulds Limited, London, England, a British Company ApplicationNovember 12, 1952, Serial No. 319,956

Claims priority, application Great Britain December 13, 1951 7 Claims.(Cl. 106-165) This invention relates to the production of artificialfilaments, threads, fibres and the like hereinafter referred to asfilaments, from viscose.

It is known that viscose filaments produced by the normal spinningprocesses have a crenulated surface and a structure which consists of askin and a core. The presence of the skin and core can be demonstratedby staining a cross-section cut from the filaments under specificconditions; such methods are described in the Textile Research Journal1945, page 443. Another method of differentiating between the skin andcore is by measuring the rate of axial diffusion of dyestuffs asdescribed in Textile Research Journal 1948, page 9. In addition to thedifference in dyeing afiinity and in swelling property between the skinand core the cellulose molecules of the skin are believed to be morehighly orientated than those of the core and for this reason it isthought that the strength of viscose fibres resides mainly in the skin.It is wellknown, for example, that industrial viscose yarns such as areused in the manufacture of tyres have a much thicker skin that thenormal textile fibres. Processes have been described in United Statespatent specifications Nos. 2,536,014, 2,535,045 and 2,535,044 forobtaining modified viscose filaments having a non-crenulated surface anda more diffuse boundary between the skin and core than unmodifiedfilaments by spinning viscose in the presence of specific Water-solublequaternary ammonium compounds, or specific bath-soluble monoamines orspecific aliphatic monoamines.

The object of the present invention is to provide a further process forobtaining modified viscose filaments.

According to the present invention a process for the production ofartificial filaments, threads, fibres and the like comprises extrudingviscose into a coagulating bath containing sulphuric acid and zincsulphate wherein the spinning is carried out in the presence of morethan A of a millimole and less than millimoles per 100 grams of viscoseof a polyalkylene polyamine having at least 3 amino groups which are notdirectly united to each other and which are primary or secondary aminogroups.

in the drawing, Figures 1 to 6 are tracings of photornicrographs of yarntreated in difierent ways. Figure 1 shows a cross-section of unmodifiedyarn. Figure 2 shows yarn into which a polyalkylene polyamine has beenintroduced in accordance with the invention. Figures 3 to 6 show yarnsinto which ditferent amounts of a polyalkylene polyamine have beenintroduced, and demonstrate the effect of varying the quantity of thepolyalkylene polyamine.

In the preferred process according to the invention the polyalkylenepolyamine is added to the viscose but if desired the polyalkylenepolyamine can be added to the coagulating bath or to both the viscoseand the coagulating bath. The preferred minimum concentration foraddition to the viscose 1s 1 millimole per 100 grams of viscose. Thefilaments obtained have a much thicker skin, and the boundary betweenthe skin and core is more difiuse than those of filaments obtained undersimilar conditions but without the addition of the polyalkylenepolyamines. By a suitable choice of the concentration of thepolyalkylene polyamine the core can be practically elminated. Thecross-sectional shape of the filaments is affected by the use of thesepolyalkylene pplyamines, for example filaments having a bean shape ordog-bone shape can be obtained. The crenulations normally found inviscose rayon filament cross-sections are absent and the filamentsobtained have a smooth surface. When axial diffusion tests are carriedout on filaments of the present invention little or no penetration ofthe dyestufi occurs. It may be necessary, for any particularpolyalkylene pol amine to carry out tests to determine the exactconcentration required to give the effects desired.

The viscose preferably has a salt figure of at least 4.

The coagulating bath may be of any desirable concentration, it maycontain sulphuric acid, sodium sulphate and zinc sulphate, and the zincsulphate concentration is preferably between 0.5 percent and 15 percent.The actual concentration of zinc sulphate used will depend on the typeof yarn being spun. Other substances may be added to the spinning bath,such as ammonium sulphate, magnesium sulphate and glucose.

Examples of suitable polyalkylene polyamines which may be used to carryout the process of the present invention are diethylene triamineNH2CH2CH2NHCH2CH2NH2 triethylene tetramineNHzCHzCHzNHCI-IzCHzNHCHaCHzNHa tetraethylene pentamine NH2CH2CH2(NHCH2CH2 3NH2 pentaethylene hexamine NHzCHzCHz (NI-ICH2CH2)4NH2 andother members of the series NHzCHzCI-Iz (NHCHzCHz nNHZ and compoundsobtained by further alkylation of these polyalkylene polyamines obtainedby condensing them with aliphatic alkylating agents containing more thanone the molecule for example 1,3-dichlorhydrin, dichlorethylene andtrimethylene bromide, for instance the condensation product of fourmoles of triethylene tetramine with three moles of 1,3-dichlorhydrin.

In addition to the non-crenulated surface and the increased thickness ofskin with its more diffuse boundary with the core, the filaments of thepresent invention have a lower water imbibition which is of considerableadvantage for textile applications. The filaments of the presentinvention are more resistant to soiling and have an improved resistanceto laundering and mechanical damage when wet.

by measuring the distance from the jet at which the filaments becomeneutral. The actual distance depends primarily upon the alkalinity ofthe viscose, the spinning speed, the spinning bath acidity, the spinningbath temper ature and the filament denier.

The advantages of the process are realized to the greatest extent whenit is used in conjunction with the Patented Mar. 5, 1957' so-called "hotstretc processin which the freshly spun filaments are subjected tostretching while it is passing through a bath of hot dilute acid asdescribed in United States patent specification No. 2,192,074.

When filaments are made by the combination of the hot stretch processand the process of the present in vention for use in the manufacture ofcomposite rubber rayon articles, for examples, tyres, the cords madefrom the filaments are of improved quality and have a greater fatiguelife than similar cords produced without the process of the presentinvention.

The invention is illustrated by the following examples in which thepercentages are by weight.

Example 1 A viscose was prepared to contain 7.5 percent of cellulose and6.5 percent of caustic soda, using 37 percent of carbon disulphide onthe weight of a-ccllulose. The viscose was cooled to Centigrade and 1millimole of diethylene triamine per 100 grams of viscose were mixed inand the viscose filtered and tie-aerated. When the salt figure hadfallen to 6.0 the viscose was spun through a jet having 750 holes each0.003 in diameter into a coagulating bath containing 9.5 percent ofsulphuric acid, 4.0 percent of zinc sulphate and 20 percent of sodiumsulphate at 48 centigrade. The length of immersion in the coagulatingbath was 18 inches and it was withdrawn from the bath on to a godet at arate of 48 metres per minute. The filaments were then stretched 65percent between the first and second godets while they were passedthrough a hot stretch bath at 95 centigrade and 70 inches long. The hotstretch liquor was made by diluting spinning bath to three times itsvolume. The yarn, of 1650 denier 750 filaments, was subsequently washed,desulphurized, a finish was applied and the yarn was dried and collectedon bobbins by means of a cap twister. The yarn obtained had a waterimbibition of 90 percent compared with 121.3 percent for an unmodifiedyarn spun at the same time and under the same conditions.

The bone dry yarn strength of the yarn was 4.70 grams per deniercompared with 4.20 grams per denier for the unmodified yarn. Theconditioned yarn had a strength of 3.29 grams per denier compared with2.94 grams per denier for the conditioned unmodified yarn.

The stained crosssections of the yarns obtained are shown in Figure 2.

Figure 2 shows clearly the dog-bone or bean-shaped form of the modifiedyarn, its non-crenulated surface, I

thick skin, and dilluse boundary between the skin and core as comparedwith the unmodified yarn in Figure l with its substantially circularcross-section, crenulated surface, thin skin and sharp boundary betweenthe skin and core.

Example 2 A viscose was prepared by the method described in Example 1but was modified by the addition of 1 millimole of triethylene tetramineper 100 grams of viscose. The viscose was spun under similar conditionsto those described for Example 1 except that the salt figure was 12.5,the spinning speed was 30 yards per minute and the hot stretch bathcontained boiling water and was two feet long. The cross-section of theyarn produced was similar to that shown by Example 1.

Example 3 Viscose containing 7.8 percent of cellulose, 6.5 percent ofcaustic soda and 2.15 percent of combined sulphur was prepared in theusual manner. When the viscose was 33 hours old from the beginning ofthe mixingstage and the salt figure was 6.5, 0.5 percent of carbon.vdisulphide on the weight of the viscose was added and was mixed in forhalf an hour at centigrade. 4 millimoles per 100 grams of viscose ofdiet hylene triamine was added and the viscose was mixed for a furtherhalf an hour. When the viscose was hours old and had a salt figure of7.6 it was ready for spinning.

The viscose was extruded through a jet having 40 holes, 0.003 inch indiameter into a coagulating bath containing 9.0 percent of sulphuricacid, 20.0 percent of sodium sulphate and 4.0 percent of zinc sulphateto give a thread of 150 denier and 40 filaments. The length of immersionin the bath was 21 inches and the temperature of the bath was 48Centigrade. The thread was drawn from the bath at a rate of 48.6 metresper minute by a godet and then travelled to a second godet rotating at ahigher speed than the first godet, to impart a 20 percent stretch to thethread. The thread was collected in a centrifugal spinning box rotatingat 7,000 R. P. M. The cake obtained was washed free from acid and dried.

The distance from the jet at which the freshly coagulated thread becameneutral was 8 inches whereas an unmodified viscose extruded undersimilar conditions became neutral 2% inches from the jet. The percentageof cellulose in the cake was 40 percent compared with 28.5 percent foran unmodified viscose. The water imbibition of the finished thread waspercent compared with 101 percent for a similar thread from anunmodified viscose. Determination of the axial diffusion of the threadwas carried out as described by Hermanns in the Textile Research Journal1948, page 9, using Solophenyl East Blue-green BL; no penetration ofdyestuff was obtained, but for thread from an unmodified viscose it was50 11. after impregnation for four hours in 1 percent solution of thedyestuff at room temperature indicating that the thread from themodified viscose showed no skin and core effect. The thread had anon-crenulate d surface and the filaments were dog-bone shape incross-section.

Example 4 Viscose containing 7.8 percent cellulose, 6.5 percent causticsoda and 2. .5 percent combined sulphur was prepared in the usual mannerand filtered. When the viscose was 16 hours old 0.5 percent of carbondisulphide was added to it and mixed in for 15 minutes. The temperatureof the viscose was reduced by cooling to 1 centigrade and divided intofour parts to which were added 1.0, 2.0, 3.0 and 6.0 millimoles pergrams viscose triethylone tetrainine. The viscoses were mi .ed for 15minutes, evacuated for eight hours and spun through a jet having 500holes, .003 inch in diameter in bath containing 9.5 percent of sulphuricacid, 20.0 percent of sodium sulphate and 4.0 percent of zinc sulphateat 48 centigrade. The filaments were drawn oil? by a godet at 18 yardsper n1inrte and stretched through a boiling water bath, by means of asecond godet having a peripheral speed oi: yards per minute. The threadwas collected in a Tcpham box revolving at 4,000 R. P. M. The yarn wassubsequently washed and dried.

The salt figures of the viscose at the time of spinning were 12.5, 11.4,ll.6 and 10.2 respectively. The stained cross-sections of the yarns areshown in Figures 3, 4, 5 and 6. in which Figure 3 is from viscose having1.0 millimolc of triethylene tetraminc per 100 grams of viscose, Figure4 is from viscose having 2.0 millimoles of triethylene tetramine per 100grams of viscose, Figure 5 is from viscose having 3 millimoles oftriethylene tctramin-e per 100 grams of viscose and Figure 6 is fromviscose having 6.0 millimoies of triethylene tetramine per 100 grams ctviscose. These figures show how the shape, smoothness of outline andskin thickness are dependent on the amount of triethylenc tetraminepresent and demonstrate that the optimum concentration for theconditions of the example lies in the region of l millimole per 100grams of viscose.

JJhat we claim is:

l. A process as claimed in claim 3 wherein the polyethylene polyarnineis diethylene triumine.

2. A process as claimed in claim 3 wherein the polyethylene polyamine istriethyleue tetramine.

3. A process for the production of viscose rayon filaments, threads,fibers and the like having a thick skin comprising extruding viscose, inthe presence of more than one quarter of a millimole and less thanmillimoles per 100 grams of viscose of a polyethylene polyaminecomponent selected from the group consisting of polyethylene polyamineshaving the general formula where n is from 1 to 4 inclusive, andcondensation products of said polyamines with aliphatic alkylatingagents selected from the group consisting of diehlorohydrin,dichlorethylene and trimethylene bromide, into a coagulating bathcontaining sulphuric acid and 0.545% of zinc sulphate.

4. A process for the production of viscose rayon filaments, threads,fibers and the like having a thick skin comprising extruding viscose inthe presence of more than one quarter of a millimole and less than 5millimoles per 100 grams of viscose of a polyethylene polyaminecomponent selected from the group consisting of polyethylene polyamines'having the general formula NH2CH2CH2(NHCH2CH2)11NH2 where n is from 1 to4 inclusive and condensation products of said polyamines with aliphaticalkylating agents selected from the group consisting of dichlorohydrin,dichlorethylene and trimethylene bromide, into a coagulatwhere n is from1 to 4 inclusive, and condensation products of said polyamines withaliphatic alkylating agents selected from the group consisting ofdichlorohydrin, dichlorethylene and trimethylene bromide.

6. Viscose as claimed in claim 5 wherein the polyethylene polyamine isdiethylene triamine.

7. Viscose as claimed in claim 5 wherein the polyethyl ene polyamine istriethyleue tetramine.

References Cited in the file of this patent UNITED STATES PATENTS1,929,868 Haller Oct. 10, 1933 2,300,589 Nelles Nov. 3, 1942 2,312,199Tallis Feb. 23, 1943 2,329,086 Robinson Sept. 7, 1943 2,345,570 BleyApr. 4, 1944 2,397,454 Woodward Mar. 26, 1946 2,422,021 Kline et al.June 10, 1947 2,535,044 Cox Dec. 26, 1950

3. A PROCESS FOR THE PRODUCTION OF VISCOSE RAYON FILAMENTS, THREADS,FIBERS AND THE LIKE HAVING A THICK SKIN COMPRISING EXTRUDNG VISCOSE, INTHE PRESENCE OF MORE THAN ONE QUATER OF A MILLIMOLE AND LES THAN 5MILLIMOLES PER 100 GRAMS OF VISCOSE OF A POLYETHYLENE POLYAMINECOMPONENTS SELECTED FROM THE GROUP CONSISTING OF POLYETHYLENE POLYAMINESHAVING THE GENERAL FORMULA